Study On Microwave Sintering Repair Device For Wear Of Carbide Roller Groove

Cemented carbide roll ring is a key component of high-speed wire rod mill with high hardness, excellent wear resistance and heat resistance, and high production efficiency. But in the process of high-speed rolling frequently subjected to alternating thermal loads, the rolling groove wears easily. In order to meet production demand, the roll ring needs to keep downtime to re-grinding. The roll ring will be no longer re-grinded and scrapped when the outer diameter of the roller ring reaches the allowable limit size. It is a great significance in the energy saving that the worn rolling groove could be timely repaired before the allowable limit size. In this study, the repair of worn rolling groove of YGH20type cemented carbide roll ring is the research object. The repair process requirements, implementation mechanism and the main factors of the worn rolling groove have been analyzed. Meanwhile the repair process of worn rolling groove based on the combination of microwave sintering and functionally graded sintering has been determined by experiment. And a corresponding repair apparatus is developed.In this study, the rolling groove wear repair mechanism has been analyzed on function and its project has been designed, as it combines microwave sintering with functionally graded materials preparation process. Make the roll ring assemble on the mandrel which the clamping mechanism owns, decompose the compacting surface with the two half torus of upper and bottom punch, and fold them as a whole torus which keep identical with the groove shape of the repaired rolling, so that them can constitute a powder mould, and then achieve powder compacting. It ensures the precise positioning of the dynamic abrasive, the transfer gap, and the uniform force in the pressing process, and the resonant cavity seal during microwave sintering on the whole mechanism. To ensure the grain of the repair layer is uniform, and avoid the flaw as porosity and segregation, the Spiral type of measure powder feeding mechanism has been studied and designed, it achieves continuous and uniform precision powdering, makes the compaction have uniformly distributed density, it has been meet the needs of the powder feeding.The compaction of the carbide gradient repair layer repression has been researched. The corrugated carbide repair layer has the gradient structure benefit from the twice compaction with bonding layer and repair layer. Via adjusting the ratio of powder of the bonding layer and repair layer, the gradient repair layer performance tuning and gradient transition has been achieved, so as to achieve the required performance of the rolling groove of roller ring. Of which compacts drive has adopted the double elbow rod linkage repression institutions to ensure the powder compacts dynamic mold consisted of the upper and lower punches and the rolling groove surface to be repaired. Besides, two-way synchronization compound die and repression has been achieved.Aim at the cyclic sintering pocess characteristics of rolling groove surface which to be repaired, require to uniform heat, insulate and pack on the it, and try to ensure the roll center area as much as possible away from thermal effects. Research and design a cylindrical cavity which the frequency is2.45GHz can meet this requirement, make the microwave electric field distribution the annular area concentrate in the rolling groove powder compaction, but there is no or only weak electric field strength on the middle of the cavity. And depend on HFSS, a finite element simulation software, analysis on the design of microwave resonant cylindrical cavity. Depend on the simulation result improving the size of the cavity. The simulation result shows that the TE311mode field cylindrical cavity is the best, it can ensure uniform heating of the repair process requirements microwave sintering.Finally, according to the repair process of worn rolling groove biased on the combination of microwave sintering and functionally graded sintering, repairing apparatus control strategy has been generated, and the corresponding repair apparatus control system has been designed. Choosing the DVP48EH00T2type PLC and DVP01PU-H2type positioning module as the control core. Eventually the automatic control of the repair apparatus has achieved.